N-Phosphonomethyl acrylamides as flame retarding agents for textiles

ABSTRACT

A process for imparting flame resistance to textile materials which comprises combining a flame retardant amount of a compound of the formula   D R A W I N G IN WHICH R is aryl or alkyl; Y is -H or lower alkyl; and Z is -H or -CH3 with a textile selected from the group consisting of a cellulosic material, a proteinaceous material, polyethylene terephthalate and blends thereof.

United States Patent Duffy et a].

[4 1 May 20, 1975 N-PI-IOSPHONOMETHYL ACRYLAMIDES AS FLAME RETARDING AGENTS FOR TEXTILES [75] Inventors: James J. Duffy, Buffalo; Peter Golborn, Lewiston, both of NY.

[73] Assignee: Hooker Chemicals & Plastics Corporation, Niagara Falls, NY.

22 Filed: Nov. 30, 1972 21 Appl. No.2 311,047

Related US. Application Data [62] Division of Ser. No. 129,138, March 29, 1971.

FOREIGN PATENTS OR APPLICATIONS 46-17317 5/1971 Japan 8/116 P Primary ExaminerStephen J. Lechert, Jr. Attorney, Agent, or FirmPeter F. Casella; Donald C. Studley; William J. Crossetta [57] ABSTRACT A process for imparting flame resistance to textile materials which comprises combining a flame retardant amount of a compound of the formula II II (R0) PCH 4|: C( ;=CH

in which R is aryl or alkyl; Y is -H or lower alkyl; and Z is --I-I or C1-I with a textile selected from the group consisting of a cellulosic material, a proteinaceous material, polyethylene terephthalate and blends thereof.

11 Claims, No Drawings N-PI-IOSPHONOMETHYL ACRYLAMIDES AS FLAME RETARDING AGENTSjFOR TEXTILES This is a division of application Ser. No. I29,l38, filed Mar. 29. l97l.

BACKGROUND OF THE INVENTION Many flame retarding agents and methods of application have been developed in attempts to obtain flame resistant textile materials. For example. mixtures of ammonium dihydrogen orthophosphate or boric acid with borax have been used to retard flame in cellulosic materials. Wash-proof finishes have been produced by depositing metal oxides within or on the fibers of cellulose by the successive precipitation of ferric oxide and a mixture of tungstic acid and stannic oxide or by successive deposition of antimony trioxide and titanium dioxide. Such processes require plural treatment baths in which strongly acidic solutions are employed. These strongly acidic solutions are both inconvenient to use and pose the problem of possible degradation of the cellulose. Furthermore, the presence of a metal oxide coating on cellulosic textile materials creates difficulties insome subsequent dyeing processes.

One process which involves the use of a single processing bath consists of padding a dispersion of achlorinated hydrocarbon and finely divided antimony oxide on the cellulosic fabric. The fabric is then heated to render the finish wash-proof. Near the combustion temperature, antimony oxide will react with hydrogen chloride, generated by degradation of the chlorinated hydrocarbon, to form antimony oxychloride which suppresses flame. The combination ofa chlorinated hydrocarbon and finely divided antimony oxide are not acceptable finishes for closely woven fabrics because they deleteriously effect the hand of the finished product.

Flame resistance has been imparted to cellulosic materials by esterification of the cellulose with diammonium hydrogen orthophosphate. Products so treated are subject to metathesis reactions with cations in aqueous solution during washing, the ammonium cation being displaced by calcium, sodium or magnesium. The flame resistance properties of the diammonium orthophosphate ester of the cellulosic material is then regenerated by reacting the washed product with an ammonium chloride solution.

BRIEF DESCRIPTION OF THE INVENTION In accordance with this invention there is provided a novel group of flame retardants for textile materials which are N-phosphonomethyl acrylami'des of the formula:

wherein R is a univalent hydrocarbon radical independently selected from the group consisting of phenyl and lower alkyl radicals of l to 8 carbon atoms:

Y is selected from the group consisting of -H and lower alkyl radicals of 1 to 8 carbon atoms;

Z is selected from the group consisting of H and CH This invention also includes methods for imparting flame resistance to textile materials by incorpo' rating into the textile a flame retardant amount of one or more of the compounds of this invention. Furthermore, the flame retardant textile composition forms a third aspect of this invention.

The compounds of this invention are prepared by conventional methods by the reaction of a tertiary phosphite and an N-hydroxymethyl acrylamide or N- hydroxymethyl methacrylamide and their N-alkylated analogs. The latter compounds being produced by the reaction of formaldehyde with acrylamide, methacrylamide or their N-alkylated derivatives.

The compounds of this invention may be applied to textile materials by conventional finishing techniques such as by thermal or radiation induced pad curing. The finished textile product, whether subjected to additional finishing treatments or not, exhibits durable, flame resistant properties. By durable, applicants mean the flame retardant is fast to plural laundering or dry cleaning treatments.

The flame retarding agents of this invention may be applied to various textiles such as cellulosic materials, proteinaceous materials, polyethylene terephthalate, and analogous man-made fibers. By cellulosic materials, applicants intend to embrace cotton, rayon, regenerated cellulose and cellulose derivatives which retain the cellulose backbone and at least one hydroxyl substituent per repeating glucose unit. By proteinaceous material applicants intend to embrace those textile materials which present the functional groups of protein, such as wool.

Of special interest is the applicability of the tire retardant agents of the instant invention to blends of cotton and polyethylene terephthalate in textile fabrics and fibers to provide a uniform, durable flame-proof finish.

DETAILED DESCRIPTION OF THE INVENTION The compounds of this invention may be prepared by the reaction sequence:

0 0 II I! ZY YZ ca on (no) 3P II II wherein R, Y and Z have the meaning given above.

The reaction of amides with formaldehyde is well known to form N-hydroxymethyl derivatives. The second step of this sequence may be described as a transesterification reaction of the unsaturated alcohol with the tertiary phosphite ester and a subsequent rearbe in the order of N-hydroxymethylamide/phosphite from about 1/1 to about l/lO. As the amide is added to the phosphite, a mole of alcohol corresponding to the phosphite used is formed and removed during the reaction. After the reaction, excess phosphite is removed by distillation under reduced pressure to yield the product which can be used as such without additional purification.

The products of this invention have advantages over the flame retardant agents of the prior art in that they may be used on a variety of textile materials ofdifferent chemical compositions and they may be applied by a variety of methods. They may be applied to materials in either the fiber or fabric form to give durable, flame resistant materials with minimum detectable physical changes in the quality of the textile material.

Cellulosic textile materials may be made flame retardant via a variety of methods. Cellulose may be treated with aqueous NaOH solutions to produce an ionic form which will add to the flame retardants of this invention. Theoretically, the reaction is by addition of the cellulose alkoxide to the (1,3 unsaturated carbonyl compound of this invention. However, applicants do not wish to be bound by this theory and intend to protect the claimed invention in whatever form or by whatever mechanism it takes. For example,

Samples of cellulosic material are immersed in a -30 percent by weight NaOH solution for l-2O minutes and squeezed to a wet pick up of 60-80% based upon the weight of cellulosic material using a two roll laboratory padder at 60 pounds per square inch gauge pressure. The samples are then dried at 200275F. from l-5 minutes in a circulating air oven. These samples are then immersed in an aqueous solution of the flame retardant of this invention (-70% by weight) for l-2O minutes and squeezed to 6080% wet weight pick up based upon the weight of textile on a laboratory padder. The materials are then cured in a circulating air oven at 200-275F. for l1O minutes to promote reaction. The samples are then washed in hot water to remove residual unreacted material and dried.

The products may also be grafted to cellulose via a free radical source generated on the cellulose backbone via electron beam irradiation. Cellulose is known to form stable free radicals under the influence of this type of irradiation.

The materials to be grafted are immersed in a solution of the phosphorus acrylamide and squeezed in a two roll laboratory padder at 60 pounds per square inch gauge pressure to about 70% wet weight pick up. The materials are then passed under an electron beam two times to give an average dose of 1.66 megarads to induce grafting. The samples are then boiled for one half hour in water to remove any homopolymer of the acrylamide which may have formed and dried.

The products of this invention may also be applied to ccllulosic materials in combination with other materials to give a cross-linking insoluble polymer. For example, the products of this invention where Y=H react with formaldehyde to give N-hydroxymethyl derivatives which react with other cellulosic finishing agents such as urea, N-methylolated urea, methylolated melamines, and like materials.

Mixtures of the products of this invention with formaldehyde solutions in the weight ratio of H1 to H3 are added to aqueous solution of cellulosic crosslinking agents such as trimethylolmelamine containing a Lewis acid catalyst such as MgCl or ZnNO .6H O.

The sample of textile material is immersed in an aqueous solution of phosphorus-acrylamide, formaldehyde, trimethylolmelamine, and ZnNO .6H O and squeezed on a two roll padder to 90% wet weight pick up. The material is dried at 200-270F for 1-3 minutes and cured at 300370F for l-6 minutes in a circulating air oven. The samples are then washed in hot water and dried.

Electron beam irradiation may also be used to pro mote stable free radicals on polyester fibers made from a dibasic acid and a diol, such as polyethylene terephthalate, and wool in addition to cellulose. Fibers or fabrics of polyester and wool may be made to react with the products of this invention at a dose of 1.66 megarads and greater to produce permanantly grafted materials by the procedure described for cotton above. In addition blends of cotton and polyester may be treated in the same manner to produce uniformly treated fire retardant fiber or fabric blends.

The following examples are presented for purposes of illustration rather than limitation of the scope of the invention. Examples l-4 illustrate the production of the flame retarding agents of this invention while examples 513 illustrate the application and flame retardant effect of the application of the agents of this invention to various textile materials. In each of examples 5-13, the process steps were performed as follows except where a specific method is otherwise indicated. Padding was done on a standard two roll laboratory padder at a gauge pressure of 60 pounds per square inch in all cases. Drying and curing during processing were done with a standard laboratory textile circulating air oven. Washing and drying were done in standard home top loading automatic washer and a tumble dryer. Flammability testing was done in accordance with (American Association of Textile Chemists and Colorists) Test Method 34-1966, the standard vertical char method.

The finished samples for testing have a flame retardant add on of from 5-40% by weight and preferably from 1025% by weight of substrate.

In each of examples 5-13, the indication of a char distance for the textile indicates self-extinguishment at that point. For comparison purposes. the corresponding non-treated textile would be completely consumed.

EXAMPLE 1 II II Prepa rat Ion of CH =CH-C-NltCH P (OCH 2 Trimethyl phosphite (186 g 1.5 mole) was placed in a round bottomed flask, fitted with a thermometer. mechanical stirrer, addition funnel. distillation head with a water condenser, and heating mantle. The phosphite was heated to 100C and N-hydroxymethyl acrylamide (100 g. 1.0 mole) added in small portions over one hour to maintain the reaction temperature at 95-105C. Methanol was removed continuously over the reaction time. After the addition was complete the mixture was held at 100c. for minutes and then cooled to room temperature. The mixture was stripped on a rotary evaporator under reduced pressure to remove residual trimethyl phosphite and yielded a clear liquid in 98.5 percent yield.

The material was characterized by infrared spectroscopy, and nuclear magnetic resonance spectroscopy. Molecular weight determination showed a molecular weight of 197, an unsaturation of 93% and elemental analyses of the isolated product as 36.4% C; 6.4% H; 6.9% N; and 16.3% P.

EXAMPLE 2 II n Preparation of cH =cH-c-NH-cH -P(ocH CH CH CH In a three necked flask fitted with a thermometer, addition funnel. heating mantle, mechanical stirrer, and distillation head with a water condenser; tributyl phosphite (250 g. 1.0 mole) was heated to 120C. Maintainshowed 49.2% C; 8.1% H; 4.7% N; 11.5% P.

EXAMPLE 3 N-methylol methacrylamide (57 g 0.5 mole) was added over 45 minutes to triethyl phosphite (83 g 0.5 mole) held at l 10C. in a three necked round bottomed flask fitted with a distillation head with a water condenser, thermometer, addition funnel, mechanical stirrer, and heating mantle. Ethyl alcohol was distilled from the reaction mixture during the addition. After the addition the mixture was held minutes at 100C. and then stripped at 70C. for one hour under vacuum on a rotary evaporator. I

The resulting product was a light yellow liquid with an elemental analysis of 48.9% C; 7.3% H; 5.7% N;

13.8% P. Infrared spectroscopy was used to confirm the product structure.

EXAMPLE 4 Preparation of cH =c-c -NH-CH2-P (001 Trimethyl phosphite (93 g 0.5 mole) was heated to 95C. in a round bottom flask fitted with a reflux condenser, mechanical stirrer, thermometer, addition funnel, and heating mantle. N-methylol methacrylamide (57 g 0.5 mole) was added over thirty minutes at 95100 and the reaction mixture then stirred at -105C. for 20 minutes. The mixture was held under reduced pressure in a distillation apparatus for one hour. THe product was isolated in 98.6% yield and had an elemental analysis of 39.9% C; 7.7% H; 6.6% N; 15.1% P. Molecular weight determination (199) and infrared spectroscopy were used as an aid in product identification.

EXAMPLE 5 II II Prepare n on of CH2=CH-C-NH-CH2-P(OCHZCHB Triethyl phosphite (500 g) was warmed to 1 15C in a three necked round bottomed flask fitted with a distillation head with reflux condenser, thermometer, mechanical stirrer, addition funnel, and heating mantle. N-methylol acrylamide (200 g) was added in small portions over 2 hours at 1 15120C and then stirred for one half hour at 120C. The excess phosphite was removed under reduced pressure on a rotary evaporator to give a quantitative yield (100%) of a clear liquid. Structure was confirmed by infrared spectroscopy, a molecular .weight determination 236 and elemental analysis, 43.1% C; 7.5% H; 6.1% N; 13.9% P.

EXAMPLE 6 Preparation of N-dimethylphosphonomethyl, N-methyl acrylamide.

A mixture of N-methyl acrylamide (1.0 mole), paraformaldehyde (1.0 mole), sodium methoxide 1 g.) and ethylene dichloride (250 ml.) is heated at 50C. for 2 hours to give a homogeneous solution. On cooling the mixture separates into two layers. The lower layer is run off, washed with ethylene dichloride twice in 250 milliliter portions and dried to give N-hydroxymethyl N-methyl acrylamide.

To trimethyl phosphite (1.0 mole) heated at 100C. is added dropwise over 1 hour N-hydroxymethyl N- methyl acrylamide (1.0 mole). The reaction temperature is kept in the range 95 to C. and methanol is removed by distillation as it is formed. When the addition is complete, the reaction mixture is held at 100 for 10 minutes, then cooled and stripped on a rotary evaporator to give N-dimethylphosphonomethyl N-methyl acrylamide.

EXAMPLE 7 A sample of cotton sheeting, 5.0 ounces per square yard, was impregnated with an aqueous solution containing 15 g of NaOH per 100 g of solution and squeezed to about 80 percent wet pick up. The impregnated fabric was then dried at 250F for two minutes. The resulting fabric was then impregnated with an aqueous solution containing about 50 g of N-dimethylphosphonomethyl acrylamide per 100 g of solution and squeezed to about 80 percent wet weight pick up. This impregnated fabric was then dried for 2.0 minutes at 250F. and cured for 2.5 minutes at 330F. The material was then washed in hot water and dried. The

treated fabric had an initial char length of 5.0 inches and a char length of 4.1 inches after washes as measured by AATCC Method 344966.

EXAMPLE 8 A sample of 5.0 ounces per square yard cotton sheeting was treated with an aqueous solution of N-diethylphosphonomethyl methaerylamide of about 50 g per 100 g of solution as in Example 1. A char length of 5.7 inches was obtained initially and 5.7 after 5 washes.

EXAMPLE 9 A sample of 5.0 ounces per square yard cotton sheeting was treated with an aqueous solution of N- dibutylphosphonomethyl acrylamide of about 65 g per 100 g of solution as in Example 1. An initial char length of 6.3 inches was obtained which was changed to 7.9 inches after five washes.

EXAMPLE 10 A sample of 5.0 ounces per square yard cotton sheeting was impregnated with an aqueous solution containing N-dimethylphosphonomethyl acrylamide, 75 parts; 37% formal in solution, parts; trimethylolmelamine, 37.5 parts; ZnN0 .6H O, 20 parts; and water; 92.5 parts. The fabric was squeezed to about 65% wet pick 4 minutes. The fabric was then given a hot water wash. An initial char of 5.9 inches was obtained and a 5.6 inch char was obtained after five washes as measured by AATCC Method 34-1966.

EXAMPLE 11 A sample of rayon staple fiber was immersed in an aqueous solution containing 10 g of NaOH per 100 g of solution for 10 minutes and then squeezed to about 60% wet pick up and dried at 250F for 3 minutes. The sample was then immersed in an aqueous solution containing 35 g of N-dimethylphosphonomethyl acrylamide per 100 g of solution for 10 minutes and squeezed to remove excess solution. The sample was then held for 6 minutes at 330F and rinsed in hot water and dried. The fiber was then twisted tightly and held in a bunsen flame. Upon removal the material was selfextinguishing. A sample not treated by the procedure described was completely consumed by the bunsen flame.

After 5 washes in hot water the material retained self extinguishing characteristics.

EXAMPLE 12 A sample of 5.0 ounces per square yard cotton sheeting was impregnated with an aqueous solution of I up, dried for 2 minutes at 250F and cured at 350F for 8 Ndimethylphosphonomethyl acrylamide containing 40 g of the amide per 100 g of solution. The fabric was squeezed to about 70% wet pick up and irradiated at a dose of 1.66 megarads of ionizing radiation. The fabric was boiled 0.5 hours in water and then dried to give about 17% weight add on. An initial char of 4.1 inches and a char of 5.0 inches'was obtained after 50 home washes.

EXAMPLE 13 A sample of 4.5 ounces per square yard of polyester fabric was impregnated with an aqueous solution containing g of N-dimethylphosphonomethyl acrylamide per 100 g of solution. The fabric was squeezed to about wet pick up and irradiated at 1.66 megarads of ionizing radiation. The fabric was boiled 0.5 hours in water and dried. An initial char of 6.0 inches was obtained and after 25 washes a char length of 715 inches was obtained.

EXAMPLE 14 A sample of about 4.5 ounces per square yard fabric of a 65/35 blend of polyethylene terephthalate to cotton was impregnated with an aqueous solution containing 60 g of N-dimethylphosphonomethyl acrylamide per 100 g of solution. The fabric was squeezed to about wet pick up and irradiated at a dose of 1.66 megarads with ionizing radiation. The fabric was boiled 0.5 hours in water and dried. The resulting fabric showed an initial char of 4.5 inches and 6.5 inches after 15 home washes.

EXAMPLE 15 A sample of wool bedford cord of approximately 8.0

ounces per square yard was impregnated with an aque-.

ous solution of N-dimethylphosphonomethyl acrylamide containing 40 g of amide per 100 g of solution. The fabric was squeezed to about wet pick up and irradiated with ionizing radiation at 166 megarads. The' material was rinsed for 0.5 hours in boiling water and dried. A char length of 0.5 inches was obtained initially and after 50 washes in hot water.

What is claimed is:

l. A process for imparting flame resistance to textile materials which comprises combining a flame retardant amount of a compound of the formula in which R is aryl or alkyl; Y -H or lower alkyl; and Z is H or CH;, with a textile selected from the group consisting of a cellulosic material, a proteinaceous material, polyethylene terephthalate and blends thereof.

2. The process of claim 1 in which said amount of flame retardant is from 5 to 40 percent by weight of textile material.

3. The process of claim 1 in which the amount of flame retardant is from 10 to 25 percent by weight of textile material.

4. The process of claim 1 in which said textile material is a blend of cotton and polyethylene terephthalate.

5. The process of claim 1 wherein the compound is of the formula 9. The processof claim I wherein the compound is of the formula I. II

5 (CH O) P- CH NHCCHCH 2 8 (CH CH O) PCH NHCC CH 6. The process of claim 1 wherein the compound is of the formula II I 2 2 2m2 2 2 10. A composition of matter comprising a textile material selected from the group consisting of a cellulosic material, a proteinaceous material, polyethylene tere- 7. The process of claim 1 wherein the compound is phthalate and blends thereof and a flame retarding of the formula amount of a compound of the formula 0 o 0 0 n n II II CH 2 c 0 NE on P(ocu 2Q (R0) PCH t lC( Z-CH cs y Y z 8. The process of claim 1 wherein the compound is of the formula in which R is aryl or alkyl; Y IS H or lower alkyl; and

0 0 Z is H or -CH;;. II II 11. The composition of claim 10 containing from 5 CH2=cH-C NH-CH2-P(0CH2CH3)2 to 40 percent by weight of fabric of said compound. 

1. A PROCESS FOR IMPARTING FLAME RESISTANCE TO TEXTILE MATERIALS WHICH COMPRISES COMBING A FLAME RETARDANT AMOUNT OF A COMPOUND OF THE FORMULA
 2. The process of claim 1 in which saId amount of flame retardant is from 5 to 40 percent by weight of textile material.
 3. The process of claim 1 in which the amount of flame retardant is from 10 to 25 percent by weight of textile material.
 4. The process of claim 1 in which said textile material is a blend of cotton and polyethylene terephthalate.
 5. The process of claim 1 wherein the compound is of the formula
 6. The process of claim 1 wherein the compound is of the formula
 7. The process of claim 1 wherein the compound is of the formula
 8. The process of claim 1 wherein the compound is of the formula
 9. The process of claim 1 wherein the compound is of the formula
 10. A composition of matter comprising a textile material selected from the group consisting of a cellulosic material, a proteinaceous material, polyethylene terephthalate and blends thereof and a flame retarding amount of a compound of the formula
 11. The composition of claim 10 containing from 5 to 40 percent by weight of fabric of said compound. 